1. Technical Field
This invention is related to mineral-releasing compost and methods of using the same for soil amendment or remediation, in particular, for immobilizing or removing heavy metals from soil.
2. Description of the Related Art
Heavy metal contamination of soil poses a major threat to human health and the ecosystem. Heavy metals are not only prevalent in the soil of mining and manufacturing sites; they are common in agricultural soil that has been treated with certain types of pesticides. Moreover, heavy metals are not necessarily contained within the original sites of the contaminating activities or events. Instead, they may leach into ground water or migrate to other sites through run-offs, causing wider spread pollution.
Conventional techniques for remediating heavy-metal contaminated soils include: immobilization and removal. Immobilization leaves the heavy metals in the soil but minimizes their bioavailability and migration. Immobilization can be achieved by solidification or stabilization by liming and using soil amendments, such as zeolites, cement, or biosolid (a treated byproduct of domestic and commercial sewage). Alternatively, heavy metals may be permanently removed from the contaminated soil by soil washing, which extracts soluble fractions of heavy metal from soil to water. Contaminated soil may also be excavated and transported to an off-site landfill, or disposed of by incineration.
These conventional techniques are typically costly, labor intensive, and environmentally inefficient. Thus, there is a need for an organic approach to soil remediation that has low environmental impact.